Method and apparatus for fluid processing a workpiece

ABSTRACT

A method and apparatus for retaining a workpiece against a workpiece holder are described. A flexible member can be used to provide a substantially uniform force to securely retain the workpiece, which can allow the workpiece to be consistently positioned in a process module. In one detailed embodiment, a barrier to fluid entry is formed between the workpiece and a ring for retaining the workpiece against a workpiece holder. This provides a reliable seal during fluid processing to prevent fluid from reaching the underside of a workpiece. In various embodiments, the workpiece holder can be used to align a workpiece in a process module or to hold one or more workpieces in a configuration that allows for higher throughput.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefits of and priority to U.S. ProvisionalPatent Application Ser. No. 60/513,761 filed on Oct. 22, 2003, which isowned by the assignee of the instant application and the disclosure ofwhich is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates generally to a method and apparatus for fluidprocessing a workpiece, and more particularly to a method and apparatusfor securely retaining a workpiece during processing of the workpiece.

BACKGROUND OF THE INVENTION

Electrodeposition, among other processes, is used as a manufacturingtechnique for the application of films (e.g., metal films) to variousstructures and surfaces, such as semiconductor wafers and siliconworkpieces. An important feature of systems used for such processes istheir ability to produce films with uniform and repeatablecharacteristics such as film thickness, composition, and profilerelative to the underlying workpiece profile.

A number of factors can prevent the formation of a uniform film. Forexample, the plating current can spread out when passing from the anodeto the cathode of the system, which can result in thicker plateddeposits near the outer edge of a workpiece. In addition, the fluiddistribution in a process chamber, particularly at an anode or cathodesurface, may not be uniform. Non-uniform fluid distribution at thecathode can cause a variation in the thickness of the diffusion boundarylayer across the workpiece surface, which can lead to non-uniform filmthickness. Moreover, inefficient fluid mixing near a surface where afilm is being deposited can result in air or gas bubbles becomingentrapped at the surface. This can inhibit further deposition in thevicinity of the gas bubble, which can cause a non-uniform deposition.Finally, if a workpiece is not securely retained in a process chamber,the position of the workpiece can change during processing, and whenfluid processing a workpiece, fluid can leak into unwanted areas if asecure, fluid-tight seal is not formed with the workpiece.

Prior art systems suffer from one or more of these limitations, and aneed therefore exists for new and improved methods and apparatus forcontrolling fluid flow and electric field distribution during the fluidprocessing of a workpiece and for reliably retaining a workpiece duringprocessing.

SUMMARY OF THE INVENTION

The invention, in various aspects, features a system and components forprocessing one or more workpieces by application and removal ofmaterials from one or more surfaces of the workpiece(s). The applicationand removal can be performed by fluid flow control and/or electric fieldcontrol at a surface of a workpiece. A workpiece can be planar orsubstantially planar, and can be thin or ultra-thin. Suitable workpiecesinclude, but are not limited to, semiconductor wafers, siliconworkpieces, interconnection substrates, and printed circuit boards. Thisfield is sometimes referred to as fluid processing or wet processing,and includes electrodeposition, electroplating, electroless plating,chemical etching, resist coating, resist stripping, dielectric coating,and workpiece cleaning, among other processes.

In one embodiment, the invention features a method and apparatus forretaining a workpiece against a workpiece holder. A flexible member canbe used to provide a substantially uniform force to securely retain theworkpiece, which can allow the workpiece to be consistently positionedin a process module. In one detailed embodiment, a barrier to fluidentry is formed between the workpiece and a ring for retaining theworkpiece against a workpiece holder. This provides a reliable sealduring fluid processing to prevent fluid from reaching the underside ofa workpiece. In various embodiments, the workpiece holder can be used toalign, e.g. precisely align, a workpiece in a process module or withfluid processing elements, such as an agitation paddle (e.g., a SHEARPLATE agitation paddle available from NEXX Systems, Inc. in Billerica,Mass.) or a shield plate. The workpiece holder can be also be used tohold one or more workpieces in a vertical configuration and/or in aback-to-back configuration for higher throughput and to reduce thefootprint of the workpiece processing system. This can increaseproductivity and reduce cost. In addition, using a modular architecturefor the processing system can allow a system layout to be optimized tothe fluid process and to the throughput requirements.

In one aspect, the invention features an apparatus for fluid sealing aworkpiece. The apparatus includes a member defining at least oneretaining feature and a ring including at least one engagement featureengageable with the at least one retaining feature of the member. Themember is flexed to provide a force to the at least one engagementfeature to cause the ring to form a barrier to fluid entry with theworkpiece. In one embodiment, the force causes the member to pull the atleast one engagement feature of the ring to cause the ring to pushagainst the workpiece to form the barrier to fluid entry. In variousembodiments, the member includes at least one flex feature adapted toprovide the force substantially normal to the plane of the member toform the barrier to fluid entry. The member can define a plurality offlex features positioned about a perimeter of the member to provide theforce at least substantially uniformly from the perimeter of the member.

In one embodiment, the apparatus also includes a workpiece holder towhich the member and the ring are removably attached. The member caninclude at least one tab section for engaging at least one tooth featureof the workpiece holder. In one embodiment, the apparatus includes abacking member adapted to apply a force to flex the member. The backingmember can include push pins to contact the member. In one detailedembodiment, the apparatus includes an inflatable bladder adjacent thebacking member for moving the backing member to apply the force to flexthe member.

In various embodiments, the ring includes a first elastomer region forforming the barrier to fluid entry with a surface of the workpiece. Thering can include a second elastomer region for forming a second barrierto fluid entry with a surface of the workpiece holder. In oneembodiment, the ring includes at least one contact adapted to form anelectrical connection with the workpiece. The workpiece can have asubstantially non-circular shape. In one detailed embodiment, theworkpiece holder defines a hole that passes from a first surface to asecond surface. The diameter of the hole is smaller than the diameter ofthe ring. The hole can be used for processing a plurality of surfaces ofthe workpiece.

In another aspect, the invention provides a method of fluid sealing aworkpiece. The method includes placing a workpiece on a ring, engagingat least one engagement feature of the ring with at least one retainingfeature defined by a member, and flexing the member to provide a forceto the at least one engagement feature to cause the ring to form abarrier to fluid entry with the workpiece. In one embodiment, the methodalso includes rotating the ring to lock the at least one engagementfeature of the ring into the at least one retaining feature of themember. In various embodiments, the member includes an over-extendedstate in which the at least one retaining feature captures the at leastone engagement feature of the ring prior to flexing the member. Invarious embodiments, the method includes depositing or dissoluting ametal or a plastic on a surface of the workpiece. In another embodiment,the method also includes testing the integrity of the barrier to fluidentry.

In still another aspect, the invention features an apparatus forapplying force to an object. The apparatus includes a substantiallyplanar, ring-shaped member defining a plurality of flex featurespositioned about a perimeter of the member. The plurality of flexfeatures provides a force at least substantially uniformly around theperimeter of the object when the member is flexed. In one embodiment,the force is provided substantially normal to the plane of the member.In various embodiments, the member defines at least one retainingfeature engageable with at least one engagement feature of a ring. Thering can retain the object while the force is applied. The force canretain the object against a portion of a surface of a workpiece holder.In one detailed embodiment, the object has a substantially non-circularshape.

In one embodiment, the apparatus also includes a backing member adaptedto apply a force to flex the member. In various embodiments, theplurality of flex features can be positioned about an inner perimeter ofthe member, about an outer perimeter of the member, or about both theinner and outer perimeters of the member. The member can be formed froma spring-like material (e.g., stainless steel or titanium).

In yet another aspect, the apparatus features a method for applying auniform force to an object. The method includes providing a memberhaving a substantially planar, ring shape, providing a plurality of flexfeatures positioned about a perimeter of the member, and flexing themember to provide a force from the plurality of flex features uniformlyaround the perimeter of an object.

In another aspect, the invention provides an apparatus for fluid sealinga workpiece. The apparatus includes a first means defining at least oneretaining feature, a ring including at least one engagement featureengageable with the at least one retaining feature, and a second meansfor flexing the first means to provide a force to the at least oneengagement feature to cause the ring to form a barrier to fluid entrywith the workpiece.

In yet another aspect, the apparatus features an apparatus for applyingforce to an object. The apparatus includes a member having asubstantially planar ring-shape, where the member defines a plurality offlex features positioned about a perimeter of the member. The apparatusalso includes a means for flexing the member to provide a force from theplurality of flex features uniformly around the perimeter of an object.

Other aspects and advantages of the invention will become apparent fromthe following drawings, detailed description, and claims, all of whichillustrate the principles of the invention, by way of example only.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of the invention described above, together with furtheradvantages, may be better understood by referring to the followingdescription taken in conjunction with the accompanying drawings. In thedrawings, like reference characters generally refer to the same partsthroughout the different views. The drawings are not necessarily toscale, emphasis instead generally being placed upon illustrating theprinciples of the invention.

FIG. 1 depicts a block diagram of an exemplary production system for aworkpiece.

FIG. 2 shows a perspective view of an illustrative embodiment of aworkpiece holder according to the invention.

FIG. 3 shows a cross-section of an exemplary workpiece holder forretaining a plurality of workpieces according to the invention.

FIG. 4 shows a cross-section of an exemplary workpiece holder accordingto the invention.

FIG. 5 depicts an exploded view of another exemplary workpiece holderaccording to the invention.

FIG. 6 shows another exploded view the workpiece holder of FIG. 5.

FIG. 7 shows a plan view of a portion of an exemplary member having aplurality of flex features according to the invention.

FIGS. 8A-8C depict diagrammatic representations of the movement andaction of the member and the flex feature(s) of an apparatus forretaining a workpiece according to the invention.

FIG. 9 depicts a perspective view of another exemplary workpiece holderincluding a hole bored through for processing a plurality of surfaces ofa workpiece according to the invention.

FIG. 10 shows an exploded view of an exemplary apparatus for processinga workpiece according to the invention.

FIG. 11 depicts a sectional view of another exemplary embodiment of anapparatus for processing a workpiece according to the invention.

FIG. 12 depicts a perspective view of an exemplary embodiment of amember for agitating a fluid during fluid processing of a workpieceaccording to the invention.

FIG. 13 shows a section view of another exemplary embodiment of a memberfor agitating a fluid during fluid processing of a workpiece accordingto the invention.

FIG. 14 shows a section view of another exemplary embodiment of a memberfor agitating a fluid during fluid processing of a workpiece accordingto the invention.

FIG. 15 depicts a diagrammatic representation of the position of aportion of a member for agitating a fluid adjacent a workpiece surfaceduring a oscillatory motion according to the invention.

FIG. 16 shows a diagrammatic representation of oscillatory motion of aportion of a member adjacent a workpiece surface for agitating a fluidaccording to the invention.

FIG. 17 shows a graphical view of an exemplary non-uniform oscillationprofile for agitating a fluid during fluid processing of a workpieceaccording to the invention.

FIG. 18 depicts a graphical view of another exemplary non-uniformoscillation profile for agitating a fluid during fluid processing of aworkpiece according to the invention.

FIG. 19 shows a graphical view of boundary layer thickness versus fluidagitation speed according to the invention.

FIG. 20 depicts a plan view of an exemplary embodiment of a plate forvarying an electric field during processing of a workpiece according tothe invention.

FIG. 21A shows a plan view of an exemplary loading station forworkpieces according to the invention.

FIG. 21B shows a side view of the loading station depicted in FIG. 21A.

DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an exemplary production system 10 for a workpiece.The production system 10 can utilize various features of the invention.The production system 10 can include a loading station 14 for deliveringa workpiece to a workpiece holder 18. The production system 10 can alsoinclude one or more modules 22, e.g., process modules, for processing aworkpiece. The loading station 14 and the one or more modules 22 can bemounted in a single framework, or in adjacent frameworks. The frameworkcan include a transport system 26 for moving a workpiece holder 18 fromthe loading station 14 to a first module and between modules. Anexemplary production system is a Stratus System available from NEXXSystems, Inc. in Billerica, Mass.

The workpiece (examples of which are shown in subsequent figures) can beplanar, substantially planar, and/or thin or ultra-thin. In variousembodiments, the workpiece has a circular shape or a substantiallycircular shape. In other embodiments, the workpiece is non-circular. Forexample, the workpiece can be rectangular, square, oval, or triangular,or have another suitable geometric configuration. In variousembodiments, the workpiece can be, for example, a semiconductor wafer,silicon workpiece, interconnection substrate, printed circuit board, orother workpiece suitable for processing. The loading station 14 can bean automated loading station, such as an automated wafer handling frontend available from Newport Automation in Irvine, Calif. or BrooksAutomation in Chelmsford, Mass.

The workpiece holder 18, according to the invention, can be used toretain a single workpiece, or a plurality of workpieces. The workpieceholder 18 can utilize a back-to-back configuration for two or moreworkpieces. Furthermore, the workpiece holder 18 can have a hole boredthrough its center for processing a plurality of surfaces of a singleworkpiece. These embodiments are described in more detail below.

Each of the one or more modules 22, according to the invention, can beused for cleaning, rinsing, drying, pretreating, plating,buffering/holding, etching, electrodepositing, electroplating,electroetching, electrodissolution, electroless depositing, electrolessdissolution, photoresist depositing, photoresist stripping, chemicaletch processing, seed layer etching, and similar processes requiringfluid flow and/or electric field control and use. In variousembodiments, the workpiece is retained by the workpiece holder 18 whileprocessing is performed. Each of the one or more modules 22 and/or theworkpiece holder 18 can be used to apply a variety of films to a surfaceof a workpiece, including, but not limited to, metal, plastic, andpolymer films. Suitable metals include, but are not limited to, copper,gold, lead, tin, nickel, and iron. In addition, alloys, compounds, andsolders of these metals (e.g., lead/tin and nickel/iron) can be appliedto a workpiece surface.

In various embodiments, the film deposited can have a thickness betweenabout 1 μm and about 150 μm. Using the features of the invention, thefilm can be high purity, and the thickness can be uniform across thesurface of the workpiece. The film can have uniform electricalproperties on (i) a flat, continuous uniform surface, (ii) on a flatcontinuous surface with micro-scale topography, and/or (iii) on a flatsurface with topography and/or photo-resist patterning.

In various embodiments, the production system 10 can include between oneand thirty modules, although additional modules can be used depending onthe application. Various novel features of the one or more modules 22are described in more detail below. Each of the one or more modules 22can include a robust and modular construction so that it can be removedfrom the production system 10. As such, the production system 10 can becustomizable for specific applications. For example, a module and aworkpiece holder can be configurable for processing different sizedworkpieces, e.g., 150, 200, 250 or 300 mm wafers, with minimal lostproduction time during customization.

In addition, the layout of a processing system, e.g., the position orsequence of one or more process modules, can be optimized for a specificfluid process or for a series of processes, which can lead to increasedthroughput. For example, a vertical line architecture, e.g., as utilizedby the Stratus system, can be combined with a dual wafer processingsystem. Deposition modules can be about 20 cm wide, and the number ofmodules can be adjusted to match the rate of the loading station. Anexemplary rate is about 40 workpieces per hour.

Furthermore, the layout of a processing system can orient a workpiece ina vertical 5 configuration. For a process or series of processes havinga long deposition time, a vertical configuration can enable asignificant number of workpieces to be processed simultaneously.

For example, for a process time longer than about 10 minutes, over 20workpieces can be processed simultaneously. In addition, in a processthat generates substantial volumes of gas or air at the workpiecesurface, e.g., electrophoretic deposition of photoresist, a verticalconfiguration can facilitate the removal of air or gas bubbles from thesurface of a workpiece.

The production system 10 itself can be manual or automated. Theproduction system 10 can include a computer that controls the operationof the loading station 14 and/or the transport system 26, as well theone or more modules 22. In one exemplary embodiment of an automatedsystem, a freshly loaded workpiece is transported from the loadingstation 14 to 1 5 the most distant module, and then subsequentprocessing returns the finished workpiece to the loading station 14.

FIG. 2 shows an illustrative embodiment of a workpiece holder 18 forretaining a workpiece 30. In this illustrative embodiment, the workpieceholder 18 includes a handle 34 that can be used to lift and/or transportthe workpiece holder 18. The handle can be engageable with the transportmechanism 26 shown in FIG. 1. The workpiece holder 18 also includes abody 38 and a ring 42 for contacting the workpiece 30. In variousembodiments, the body 38 of the workpiece holder 18 is formed from aplastic, such as high density polyethylene (HDPE) or polyvinylidenefluoride (PVDF). The body 38 can also include a guide strip (shown inFIGS. 5 and 6) formed in at least one edge 44. The guide 25 strip(s) canbe used to align the workpiece holder 18 in one of the modules 22.

The ring 42 can press, hold, and/or retain the workpiece 30 against thebody 38 of the workpiece holder. Contact between the workpiece 30 andthe ring 42 occurs at the outer perimeter of the workpiece 30, e.g., bycontacting less than 2 mm of the outer perimeter of the workpiece 30. Invarious embodiments, the ring 42 includes a flexible member encased inan elastomer. Portion(s) of the elastomer can be used to contact theworkpiece 30, and, in some embodiments, can create a seal with theworkpiece 30.

In various embodiments, the ring 42 can have a circular shape, asubstantially circular shape, or be non-circular (e.g., rectangular,square, oval, or triangular, or have another suitable geometricconfiguration). In one embodiment, the ring 42 has a low profilerelative to the workpiece 30. For example, in one detailed embodiment,the ring 42 extends less than about 1 mm beyond the plane of the exposedsurface of the workpiece 30. In various embodiments, the ring 42 can bea contact ring or a sealing ring. In one embodiment, the ring 42 is thesealing ring assembly described in U.S. Pat. No. 6,540,899 to Keigler,the entire disclosure of which is herein incorporated by reference.

FIG. 3 depicts a cross-section of an illustrative embodiment of aworkpiece holder 18′ that can be used to retain a plurality ofworkpieces 30. The body 38 of the workpiece holder 18′ includes a firstsurface 43 in a first plane and a second surface 45 in a second plane(e.g., a front surface and a back surface). Each surface has associatedwith it a ring 42 for retaining a respective workpiece 30, e.g., forretaining the respective workpiece 30 against the respective surface 43or 45 of the workpiece holder 18′. For example, a first ring can retaina first workpiece on the first surface of the workpiece holder in thefirst plane, and a second ring can retain a second workpiece on thesecond surface of the workpiece holder in a second plane.

According to the embodiment illustrated in FIG. 3, the first and secondplanes are parallel to each other and spaced apart. In variousembodiments, the first and second planes form an angle. In oneembodiment, the first and second planes are orthogonal. In otherembodiments, the first and second planes form either an acute angle oran obtuse angle. It is understood that the invention is not limited to aworkpiece holder with only two planes. Embodiments using a single planeor more than two planes can be used. Two planes are used here toillustrate an exemplary embodiment of an apparatus retaining a pluralityof workpieces.

In one embodiment, the workpieces are held in a back-to-backconfiguration, and, in a detailed embodiment, the workpieces arecentered on each other in the back-to-back configuration. In someembodiments, the workpieces are held on distinct surfaces of theworkpiece holder and are offset from one another. In another embodiment,a plurality of workpieces can be held on a single surface of a workpieceholder, e.g., in a side-by-side configuration. In some embodiments, aplurality of workpieces can be held on one surface of a workpieceholder, while at least one additional workpiece is held on a secondsurface of a workpiece holder.

FIG. 4 illustrates a cross-section of another embodiment of a workpieceholder 18″, which shows an exemplary system for retaining the workpiece30 against the workpiece holder 18″. A ring 42′ holds the workpiece 30against a body 38′ of the workpiece holder 18″. The workpiece 30contacts the body 38′ at a contact point 46. The body 38′ can define arecess 50 so that the workpiece 30 only contacts a portion of the body38′.

According to the illustrated embodiment, the body 38′ of the workpieceholder 18″ defines a groove 54 for holding at least a member 58, abacking member 62, and a bladder 66. The member 58 is flexible, and canalso be referred to as a flexure plate. The member 58 can have acircular shape, a substantially circular shape, or be non-circular(e.g., rectangular, square, oval, or triangular, or have anothersuitable geometric configuration). In some embodiments, the member 58can be a ring or a plate, and in one detailed embodiment, can have asubstantially planar ring-shape. In various embodiments, the member 58can be formed from a spring-like material, such as stainless steel ortitanium. The member 58 can include at least one retaining feature(e.g., as shown in FIGS. 5 and 6) that can engage at least oneengagement feature of the ring, for example, engagement feature 70 ofthe ring 42. In various embodiments, the ring 42′ and the member 58 areremovably attached to the workpiece holder 18″.

The backing member 62 can be a plate or a push plate, and can include atleast one push pin 74. In various embodiments, the backing member 62 canhave a circular shape, a substantially circular shape, or benon-circular. In various embodiments, the backing member 62 can be aring or a plate. The backing member 62 can be formed from a metal, aplastic, or a polymer material. The bladder 66, which can be a pneumaticbladder, defines a cavity 78 that can be filled with a fluid, such asair, to inflate the bladder 66. When inflated, the bladder 66 pushesagainst the backing member 62 causing the at least one push pin 74 tocontact the member 58, which causes the member to flex. The bladder 66can have a circular shape, a substantially circular shape, or benon-circular, and, in various embodiments, can be a ring or a plate. Invarious embodiments, the bladder 66 can be formed from afluoroelastomer, urethane, or mylar material.

FIGS. 5 and 6 show exploded views of another exemplary workpiece holder18′″ for retaining the workpiece 30. FIG. 5 shows the view from a firstperspective, and FIG. 6 shows the view from a second perspective. Thisembodiment of the workpiece holder 18′″ includes the ring 42′, thegroove 54, the backing member 62, and the bladder 66. The workpieceholder 18′″ can also include a handle 34′ and a member 58′.

The workpiece holder 18′″ shown in FIGS. 5 and 6 also includes a body38″, which can include a guide strip 82. In one embodiment, the recess50 defined in the body 38″ includes multiple contact points 46 forproviding support to the workpiece 30. In the illustrated embodiment,the body 38″ includes at least one port 86 for providing a fluid to thebladder 66 and/or vacuum to the underside of the ring 42′ via ducts (notshown) in the body 38″. In various embodiments, the body 38″ can alsoinclude at least one electrical contact 90 to communicate electricalcurrent to the workpiece 30. The backing member 62 can be connected to astud 92 that is engageable with the body 38″. The stud 92 provides aforce to contact the backing member 62 to the member 58′.

The ring 42′ illustrated in FIG. 6 includes at least one engagementfeature 70, which, in one embodiment, is formed as one or more studs. Asealing groove 94 can circumscribe the outer perimeter of the ring 42′.The sealing groove 94, which can be an elastomer region of the ring 42′,can mate with a sealing boss 98 that can circumscribe a perimeter of theworkpiece holder 18′″. In one embodiment, this mating forms a barrier tofluid entry, e.g., a fluid-tight seal, between the workpiece holder 18′″and the ring 42′.

In various embodiments, the ring 42′ also includes an inner sealingsurface 102 that can form a barrier to fluid entry with the workpiece30. The inner sealing surface 102 can form an electrical connection withthe workpiece 30 as well. For example, the inner sealing surface 102 caninclude flexure fingers that contact the workpiece 30. The flexurefingers can include exposed terminal tips for making electrical contact.The electrical current path can carrying up to 75 amps of electricalcurrent to the workpiece surface and can allow for independentelectrical current control to a plurality of workpieces.

In various embodiments, the inner sealing surface 102 can include anelastomer region that is deflected under sufficient force to form abarrier to fluid entry.

In some embodiments, the member 58′ defines at least one retainingfeature 110 and at least one flex feature 114. The member 58′ caninclude at least one tab section 118. The features of the member 58′ canbe cut, e.g., laser cut, into the member 58′. The at least one retainingfeature 110 can be engageable with the at least one engagement feature70 of the ring 42′. In various embodiments, the at least one retainingfeature 110 can be a keyhole slot or a capture slot cut into the member58′. In one embodiment, the at least one flex feature 114 has a ram'shead shape.

In one embodiment, the member 58′ defines a plurality of flex features114. In combination, the plurality of the flex features 114 can providean effective long path around the main body 122 of the member 58′ toallow for substantial flexing of the member 58′. In one embodiment, theplurality of flex features 114 can provide a force at leastsubstantially uniformly around the perimeter of an object, e.g., aworkpiece 30, when the member is flexed. The force can be providedsubstantially normal to the plane of the member 58′. When the force isapplied, the ring 42′ can retain the object. The flex feature(s) 114, inthis embodiment or in other embodiments, can be formed about a perimeterof the member 58′, e.g., an inner perimeter, an outer perimeter, or onboth the inner and outer perimeters.

In some embodiments, the groove 54, e.g., a ring shaped cavity definedin the body 38″, can include at least one tooth feature 126 that canengage at least one tab section 118 of the member 58′. When a pluralityof tab sections 118 are flexed away from the main body 122, a forcearises between the tab sections 118 perpendicular to the plane of theworkpiece 30.

Referring to FIGS. 5 and 6, the ring 42′ and the member 58′ can beremovably attached to the workpiece holder 18′″. In one embodiment, oneor more engagement features 70 of the ring 42′ can be engaged by (e.g.,inserted or attached) one or more retaining features 110 of the member58′. In an embodiment using keyhole slots, for example, the ring 42′ canbe rotated by several degrees until the engagement feature(s) 70 stopagainst the narrower end of the retaining feature(s) 110. This causesthe shoulder of the engagement feature(s) 70 to lie behind the member58′. The bladder 66 can then be partially or entirely deflated. Flexureforce formed by the flex features 114 causes the member 58′ to deflectand pull against the one or more engagement features 70. In thisembodiment, this pulls the ring 42′ toward the workpiece holder 18′″.

In one embodiment, flexing a member provides a force to at least oneengagement feature to cause a ring to form a barrier to fluid entry witha workpiece. For example, the force can cause the member 58′ to pull theat least one engagement feature 70 of the ring 42′ to cause it to pushagainst the workpiece 30 to form the barrier to fluid entry. The atleast one flex feature 114 can be adapted to provide the forcesubstantially normal to the plane of the member 58′ to form the barrier.The flex feature 114 can be positioned about a perimeter of the member58′ to provide the force at least substantially uniformly from theperimeter (e.g., an inner perimeter, an outer perimeter, or as shown inFIGS. 5 and 6, both the inner and outer perimeters.) The force deformingthe member 58′ can be about one kilogram per linear centimeter of thering's 42′ perimeter.

To remove a first workpiece from the workpiece holder or to exchange afirst and second workpiece, the force between the member 58′ and thering 42′ can be removed by inflating the bladder 66 so that the backingmember 62 contacts the member 58′ (with or without push pins 74) todeform it. The force engaging the engagement feature(s) 70 is relaxed sothat they can be disengaged from the retaining feature(s) 110. In oneembodiment, the force engaging the engagement feature(s) 70 is relaxedso that the ring 42′ can be rotated and moved away from the workpieceholder 18′″. The first workpiece can be removed from the ring 42′, andif desired, a fresh workpiece can be disposed on the ring 42′.

In one embodiment, the fluid seal can hold the workpiece with sufficientforce to prohibit fluid intrusion even when all power to the processingsystem is lost due to an unforeseen event. In one embodiment, thebarrier to fluid entry can be tested after a workpiece loading procedureand/or prior to processing a workpiece to ensure a workpiece has beenproperly loaded. For example, a small vacuum, e.g., about minus 0.05atm, is applied to the cavity of the workpiece holder 18′″. The vacuumcan be applied, for example, to the recess 50. The path to the vacuumcan then be closed off, and the leak-up rate of the vacuum can bemeasured. If the vacuum in the workpiece holder 18′″ does not change bymore than a prescribed amount over a defined time period, then theintegrity of the barrier is considered to be verified (e.g., about 10percent in less than about 5 seconds). If the vacuum changes at a fasterrate, the ring 42′ may not be mounted properly, and the workpiece can beunloaded and reloaded.

FIG. 7 shows a detailed view of a portion 128 of the member 58′,including retaining features 110, flex features 114, and tab sections118. As illustrated, the member 58′ defines lines 130 and 134 extendingabout the inner and outer perimeters of the member 58′, respectively.The lines 130 and 134 are cut at least substantially through the mainbody 122. In one detailed embodiment, the lines 130 and 134 are cutthrough the main body 122. The lines do not extend continuously aboutthe perimeters. Instead, the lines 130 and 134 are series of distinctlines. For example, line 130 a extends from a first retaining features114 a to an adjacent flex features 114 b. The line 130 a terminates inthe two tear-drop shaped regions 138 a and 138 b defined in the flexfeatures 114 a and 114 b, respectively. According to the illustratedembodiment, the flex feature 114, 114 a or 114 b also includes anΩ-shaped line 142. In one embodiment, two proximate tear-drop shapedregions and an Ω-shaped line combine to form an individual flex feature.The flex feature can have a ram's head shape.

In one embodiment, using a series of distinct lines can provide asubstantially long path around a perimeter of the member along which themember can be flexed. Furthermore, using a series of distinct lines canpromote an at least substantially uniform force from the perimeter.

In various embodiments, the tab sections 118 include a notch 146. In oneembodiment, the notch 146 interfaces with a corresponding catch in agroove 54 of the workpiece holder. The notch 146 can prevent the member58′ from rotating. The member 58′ can include outer tab sections 148,which can be used to retain the member 58′ in the workpiece holder.

The movement of the member 58 or 58′ and the action of the flexfeature(s) 114 can be shown diagrammatically. For illustrative purposesand without being bound to theory, FIGS. 8A-8C show diagrammaticrepresentations.

FIG. 8A shows the member 58 or 58′ in a relaxed state. Plate 150 andsprings 154 represent the member 58 or 58′. The flex feature(s) 114 canact like springs 154 to apply force. Anchor points 138 representrestraining features of a workpiece holder. For example, the anchorpoints 138 can be the tooth feature(s) 126 formed in the groove 54 ofthe workpiece holder. The anchor points 138 can restrain the tabssections 118 of the member 58 or 58′.

FIG. 8B shows a portion of the ring 42 or 42′, including the engagementfeature 70 (shown as a stud in FIGS. 8B and 8C). A force 162 is appliedto the plate 150 (i.e., the member 58 or 58′) to flex the member 58 or58′ into an overextended state. When overextended, engagement betweenthe ring 42 or 42′ and the member 58 or 58′ can be made (e.g., in oneembodiment, the retaining feature captures the engagement feature). In adetailed embodiment, engagement occurs between the engagement feature 70and the retaining feature 110. In one embodiment, the force 162 isapplied by the backing member 62. The springs 154 (i.e., the flexfeatures 114) exert a force 166 in substantially the opposite directionas the force 162.

FIG. 8C depicts the apparatus in a state where the member 58 or 58′ isapplying the force 166 to the engagement feature 70 via its retainingfeature 110. The springs 154 exert the force 166 substantially normal tothe plane of the member 58 or 58′. In one embodiment, the force 166causes the member 58 or 58′ to pull the engagement feature 70, whichcauses the ring 42 or 42′ to contact the workpiece 30. This contact canform a barrier to fluid entry between the workpiece 30 and the ring 42or 42′.

FIG. 9 depicts another exemplary embodiment of a workpiece holder 170.This embodiment can be used to process a plurality of surfaces of theworkpiece 30. The workpiece holder 170 includes a ring 42 for retainingthe workpiece. The body 174 of the workpiece holder 170 defines a hole178 bored through from a first surface 182 to a second surface 186. Thediameter of the hole 178 is smaller than the diameter of the ring 42. Invarious embodiments, the workpiece holder 18′″ includes the featuresdescribed above including, but not limited to, the member 58 or 58′, thebacking member 62, and the bladder 66. The underside of the workpiece 30and the edge of the hole 178 can form a seal to isolate these componentsfrom the fluid used in the fluid processing.

FIG. 10 shows an exemplary apparatus for processing (e.g., fluidprocessing) a workpiece. The apparatus can include a module 22, whichitself can include a housing 200. In one embodiment, the module 22contains a fluid, e.g., the housing 200 defines a cavity in which thefluid can be disposed. As illustrated in FIG. 10, the apparatus alsoincludes an embodiment of the workpiece holder 18, a member 204, a plate208, and an anode 212. In some embodiments, one or more of theseelements are not used or are not present. Variations are described inmore detail below. In various embodiments, the member 204, the plate 208and/or the anode 212 are disposed within the module 20 and/or thehousing 200. Because of the modular design, these elements can beremovably or fixably disposed within the housing 200.

In FIG. 10, the workpiece holder 18 is shown removed from the housing200. The workpiece holder 18 need not be integrated with the module 22or the housing 200. In one detailed embodiment, the workpiece holder 18is removable from the housing 200. The workpiece holder 18 can betransportable between two or more modules 22. The housing 200 caninclude grooves defined in the inner surface of two opposing sides. Theedges 44 of the workpiece holder 18 or the guide strips 82 of theworkpiece holder 18′″ can be inserted into the grooves.

An exemplary housing 200 can be less than about 180 mm in length forelectrodeposition or electroetch applications. For applications that donot require a plate 208 or an anode 212, the length can be about 75 mm.The width of the housing 200 can be between about 300 mm and about 500mm. In an exemplary embodiment for a 200 mm workpiece, the moduledimensions can be about 180 mm by 400 mm, although the dimensions canvary depending on the application and/or workpiece size.

In various embodiments, the member 204 is a paddle assembly or a fluidagitation paddle. In one detailed embodiment, the member 204 is a SHEARPLATE agitation paddle. The member 204 can be moved substantiallyparallel to a surface of a workpiece being retained by the workpieceholder 18. The member 204 can be moved with a non-uniform oscillatorymotion to agitate the fluid. In various embodiments, the oscillationfrequency of the member 204 can be between about 0 Hz and about 20 Hz,although the frequency can be higher depending on the application. Inone embodiment, the oscillation frequency of the member 204 is betweenabout 4 Hz and about 10 Hz. In one detailed embodiment, the oscillationfrequency is about 6 Hz.

In some embodiments, the member 204 is moved by one or more motors 216.The member 204 can be connected to the motor(s) 216 using connectionrods 220. In one detailed embodiment, the motor(s) 216 are linear drivemotors or a linear motor assembly. Suitable linear motors include lineardrive motors available from the LinMot Corporation in Delavan, Wis. Invarious embodiments, the motors 216 can be fixably or removably attachedto the housing 200. The motors 216 can be positioned on the center planeof the housing 200. In one detailed embodiment, the weight of the member204 and the inertial forces incurred during reciprocating motion of themember 204 is supported by the linear motors via the magnetic fieldforces between the motor slider and the motor windings rather than bymechanical bearings. The one or more motors 216 can be computercontrolled.

In various embodiments, the plate 208 can be a shield plate or shieldassembly. The plate 208 can be used to shape the electric field incidenton a surface of a workpiece being retained by the member 204. The plate208′ can be formed from a non-conducting materials. Suitable materialsinclude, but are not limited to, HDPE and PVDF. In various embodiments,the plate 208 can have a circular shape, a substantially circular shape,or be non-circular (e.g., rectangular, square, oval, or triangular, orhave another suitable geometric configuration). A feature of the plate208 is that it can be removed and replaced with little effort. Thisallows a single module to be configurable for processing different sizedworkpieces with minimal lost production time.

In one embodiment, the anode 212 forms the outer wall of the housing200. In one embodiment, the anode 212 can be a component of an anodeassembly, which forms the outer wall of the housing 200. In variousembodiments, the housing 200 has an outer wall and either the anode 212or the anode assembly are removably attached the wall or spaced from thewall.

In various embodiments, the anode 212 can be a copper disk. In oneembodiment, the exposed surface area of the anode 212 is about 300 cm².In one embodiment, the anode 212 is consumed during electrodeposition oranother fluid process such as copper or solder deposition. One featureof the anode 212 is that it can be removed and replaced with littleeffort, minimizing lost production time.

In embodiments using an anode 212, the workpiece surface serves as thecathode. It is noted that in some embodiments, it is preferred that thepolarity of the system is reversed. That is, the workpiece surface iscontrolled to be anodic relative to a cathode placed in the module 22.In such an embodiment, the anode 212 would be replaced by a cathode.

FIG. 11 shows cross-section of another exemplary embodiment of anapparatus for processing a workpiece. This embodiment can be used, forexample, to process two workpieces simultaneously. A housing 200′includes a side wall 224 and end walls 226, and the relative positioningof members 202, members 204 a and 204 b, plates 208 and anodes 212 isshown. These elements or the distances are not shown to scale. Althoughthe members 204 a and 204 b are shown as two separate structures, theycan form a single assembly.

In an embodiment of the housing 200′ for fluid processing, fluid entersthe housing 200′ through at least one port 228 in a bottom wall of thehousing 200′. The port 228 can, in some embodiments, be located in acenter portion of the bottom wall 230 of the housing 200′. In oneembodiment, the port 228 can be positioned in a bottom portion of a sidewall 224. The fluid flows up along the surfaces of the one or moreworkpieces. The fluid can flow between the workpiece holder 18 and therespective member 204, 204 a, or 204 b or between the workpiece holder18 and the plate 208. In various embodiments, the fluid exits thehousing 200′ through the top of the housing, through a top portion of aside wall 224, or through a top portion of an end wall 226. Arrows showthe general direction of flow.

In various embodiments, the flow rate can be between about 20 liters perminute and about 40 liters per minute. In one detailed embodiment, theflow rate is about 28 liters per minute. In one embodiments, the fluidis an electrolyte. The electrolyte can be circulated through the housing200′ from a reservoir during the process. The turnover rate can be about0.8 minutes at a flow rate of about 27.6 liters per minute. An exemplarysolution can include copper sulfate, water, sulfuric acid, andhydrochloric acid.

The distance between a workpiece 30 and the respective member 204, 204a, or 204 b can be about 1 mm and about 5 mm, although the distance canvary depending on the application. In one embodiment, the member 204,204 a, or 204 b is positioned less than about 2 mm from the surface ofthe workpiece 30. The shorter the distance between the elements, thebetter is the fluid mixing at the surface. In a detailed embodimentwhere the ring 42 extends about 1 mm from the outer surface of theworkpiece, the member 204, 204 a, or 204 b can move in a plane about 1.5mm from the surface of the workpiece 30. The plate 208 can be positionedbetween about 2 and about 20 mm from the surface of the workpiece 30,although the distance can vary depending on the application. In onedetailed embodiment, the plate 208 is positioned about 5 mm from theworkpiece surface.

FIG. 12 depicts a perspective view of an exemplary embodiment of amember 204′ for agitating a fluid during fluid processing of aworkpiece. The member 204′ includes a first plate 232 and a second plate234. Each plate 232 and 234 defines a series of spaced openings 236. Theshape of the spaced openings 236 can be, for example, oval orrectangular. Each plate 232 and 234 can also include a series of spacedblades 240 for agitating the fluid. The profile of the spaced blades 240can be straight, angled, cup-shaped, or square. The center points of theseries of spaced openings 236 or the series of spaced blades 240 can bepositioned in a substantially equidistant periodic array. For example,the centers can be positioned with about 10 to about 30 mm between them.In one detailed embodiment, the centers are position about 20 mm apart.

In one embodiment, the series of spaced openings 236 agitates the fluidwhen the member 204′ is moved. In one embodiment, the series of spacedblades 240 agitates the fluid when the member 204′ is moved. In oneembodiment, both the openings 236 and the blades 240 agitate the fluid.In one detailed embodiment, an edge surface of a spaced blade 240agitates the fluid.

The plates 232 and 234 can be formed from a suitable metal, plastic, orpolymer. Suitable metals include titanium, stainless steel, or aluminum.Suitable plastics include polyvinyl chloride (PVC), chlorinated PVC(CPVC), HDPE, and PVDF. In various embodiments, either of the plates 232and 234 can be positioned between about 2 mm and about 10 mm from thesurface of the workpiece, although smaller or larger distances can beused depending on the application. In a detailed embodiment, thethickness of at least one of the plates 232 and 234 is between about 3mm and about 6 mm, although smaller or larger distances can be useddepending on the application and/or the construction of the material.Relatively thin pieces can be used so that the plate 208 can bepositioned as close to the workpiece as possible. This improves theuniformity of deposition.

The first and second plates 232 and 234 can be joined by one or morespacer features 244 and to form the member 204′. In FIG. 12, the firstand second plates 232 and 234 are shown attached to the spacer features244 by screws 248, although other means may be used, including, but notlimited to, rivets, glues, epoxies, adhesives, or outer suitableattachment means. The plates 232 and 234 and the spacer features 244 candefine a cavity in which an embodiment of the workpiece holder 18 can beinserted during processing. The spacer features 244 can facilitatealignment of the member 204′ to the workpiece holder 18.

In various embodiments, the member 204 or 204′ can be aligned to theworkpiece holder 18 by the housing 200 in a manner that offers highprecision without requiring mechanical support of the member 204 or204′. As described above, the motors 216 can support the member 204 or204′. Precise and consistent separation between the member 204 or 204′and the workpiece holder 18 can be achieved using guide wheels (notshown) mounted on the housing 200. The guide wheels can turn freely onan axle that is securely mounted on a side wall of the housing 200.Alignment wheels can also be mounted the housing 200 for positioning theworkpiece holder 18. The relationship between the guide wheels and thealignment wheels can be such that the member 204 or 204′ to theworkpiece surface is consistent to within less than about ¼ mm. Thispromotes a substantially uniform fluid boundary layer to occur at theworkpiece surface when the member 204 or 204′ is moved substantiallyparallel to the workpiece surface.

The axles for guide wheels can serve as journal bearing shafts. Themember 204 or 204′ can be moved with virtually zero frictional orbearing forces, which can significantly reduce repair and maintenancecosts that are associated with systems that use load bearing frictionalsurfaces or bearings.

FIG. 13 shows a cross-section of another exemplary embodiment of amember 204″ for agitating a fluid during fluid processing of aworkpiece. The spaced blades 240′ have a cup shape. In FIG. 13, thespaced bladed 240′ are shown adjacent the workpiece 30 being retained onthe workpiece holder 18 using the ring 42. In various embodiments, theseries of spaced openings 236 and/or the series of spaced blades 240′agitate the fluid when the member 204″ is moved. In one embodiment, anedge surface of a spaced blade 240′ agitates the fluid. In thisembodiment, the edge surface can be a side surface, a pointed surface,or a rounded surface.

FIG. 14 shows a cross-section of another exemplary embodiment of amember 204′″. The spaced blades 240″ have an angled profile, and areshown adjacent the workpiece 30 being retained on the workpiece holder18 using the ring 42. In various embodiments, the series of spacedopenings 236 and/or the series of spaced blades 240″ agitate the fluidwhen the member 204″ is moved.

As described above, the member 204, 204′, 204″ or 204′″ (referred toherein collectively as 204 x) can be used to agitate the fluid. In someembodiments, the member 204 x can be moved using a non-uniformoscillation profile. In one exemplary embodiment, the non-uniformoscillatory motion includes a reversal position that changes after eachstoke of the non-uniform oscillatory motion.

For example, referring to FIG. 15, a blade 240, 240′, or 240″ or acenter point of a spaced opening 236 (referred to herein collectively asa center point 252) adjacent a particular workpiece point 256 on asurface of the workpiece 30 need not return to the same workpiece point256 after one complete oscillation stroke. The center point 252 cantravel along the surface of the workpiece 30 as the member 204 xoscillates, and after one complete oscillation stroke, the center point252′ can be at a nearby workpiece point 260.

In one embodiment, the non-uniform oscillatory motion includes a primaryoscillation stroke and at least one secondary oscillation stroke. Thelength of the primary oscillation stroke can be substantially the sameas the separation of the spaced openings 236 defined by the member 204x. In one detailed embodiment, the length of the primary oscillationstroke can be substantially the same as the separation of adjacentspaced openings 236.

Referring to FIG. 16, an exemplary primary oscillation stroke 264 canchange a reversal position of an oscillation stroke of the member 204 x.In one detailed embodiment, the primary oscillation stroke 264 changes areversal position 268 of the center point 252 of the member 204 x. Anexemplary first secondary oscillation stroke 272 can change a reversalposition of an oscillatory motion of the member 204 x. In one detailedembodiment, the first secondary oscillation stroke 272 changes areversal position 276 of the center point 252. In various embodiments,this can also be understood as changing a reversal position of theprimary oscillation stroke 264. An exemplary second secondary stroke 280can change a reversal position of an oscillatory motion of the member204 x. In one detailed embodiment, the second secondary stroke 280changes a reversal position 284 of the center point 252. In variousembodiments, this can also be understood as changing a reversal positionof the first secondary oscillation stroke 272.

As illustrated, a center point 252 is used to show the relative motionof the member 204 x. Any point X along the surface of the member 204 x,though, can be used to show the change in reversal position of thatpoint X as the member 204 x moves. In some embodiments, the member canbe formed from a plurality of pieces. Each piece includes one or morespaced openings or one or more spaced blades. In one embodiment, eachpiece can be connected to a separate motor so that its motion isindependent of a proximate piece. In one embodiment, each piece can beconnected to the same motor so that the pieces move in concert. In someembodiments, the plurality of pieces is positioned on the same side of aworkpiece so that the motion of two or more pieces of the member 204 xagitates the fluid.

FIG. 17 shows a graphical representation of an exemplary non-uniformoscillation profile 288 for agitating a fluid during fluid processing ofa workpiece. The exemplary workpiece 30 and center point 252 in FIGS. 15and 16 are referenced for illustrative purposes. The position of thecenter point 252 of the member 204 x relative to the workpiece point 256on the surface of the workpiece 30 is plotted versus time. In thisembodiment of the member 204 x, the separation of the center points 252is about 20 mm. The primary oscillation stroke is substantially the sameas the separation between the center point 252 and an adjacent centerpoint of the member 204 x. The secondary oscillation stroke is about 40mm. Line 292 shows the relative travel of the center point as a resultof the primary oscillation stroke. Line 296 shows the relative travel ofthe center point as a result of the secondary oscillation stroke.

By using a combination of primary and secondary strokes, the reversalposition of the oscillation pattern in front of the workpiece 30 canchange sufficiently relative to the process time. This can preclude anon-uniform time averaged electric field or fluid flow field on thesurface of the workpiece. This can minimize an electric field image or afluid flow image of the member on the surface of the workpiece, whichimproves the uniformity of a deposition.

FIG. 18 shows a graphical representation of another exemplarynon-uniform oscillation profile 300 for agitating a fluid during fluidprocessing of a workpiece. In this embodiment of the member 204 x, theseparation of the center points 252 is about 20 mm. The primaryoscillation stroke is substantially the same as the separation betweenthe center point 252 and an adjacent center point of the member 204 x.The first secondary oscillation stroke is about 30 mm. The secondsecondary oscillation stroke is about 40 mm. The oscillatory motion caninclude additional secondary oscillation strokes. Line 304 shows therelative travel of the center point as a result of the primaryoscillation stroke. Line 308 shows the relative travel of the centerpoint as a result of the first secondary oscillation stroke. Line 312shows the relative travel of the center point as a result of the secondsecondary oscillation stroke.

The period of the first secondary oscillation stroke is about 2 seconds,and the period of the second secondary oscillation stroke is about 10seconds. This can move the position at which the oscillation reversaloccurs, which can spread the reversal point of each spaced blade or thecenter point of each spaced opening by about 0.1 mm. This can reduce orsubstantially eliminate any imaging of the reversal position onto theworkpiece surface.

Oscillation of the member 204 x can also form a non-periodic fluidboundary layer at the surface of the workpiece 30. In one embodiment,the member 204 x reduces fluid boundary layer thickness at the surfaceof the workpiece 30. In one detailed embodiment, the fluid boundarylayer thickness is reduced to less than about 10 μm. Furthermore, motionof the member can reduce or substantially eliminate entrapment of air orgas bubbles in the fluid from the surface of the workpiece 30. In onedetailed embodiment, fluid flow carries the air or gas bubbles near agrowing film surface in a housing 200 for plating or depositing.

FIG. 19 illustrates a graphical representation of boundary layerthickness at a surface of a workpiece versus fluid agitation rate. Thefluid agitation rate can be the oscillation rate of the member 204 x. Asillustrated, the fluid boundary layer thickness is reduced from about 55μm to less than about 10 μm as the rate is increased. The boundary layerthickness can be derived from limiting current measurements, which canbe determined by comparison to known behavior of a reference electrode,by linear sweep voltammetry, or by chronoamperometry. Fluid mixing isinversely proportional to the boundary layer thickness. Therefore,decreasing the boundary layer in a fluid process can improve fluidmixing at a workpiece surface. This can improve throughput anduniformity, and can also decrease materials consumption.

FIG. 20 depicts an exemplary embodiment of a plate 208′ for varying anelectric field during processing of a workpiece 30. Varying the electricfield at the workpiece surface can promote uniform deposition of a film,although the electric potential drop through the workpiece surfacevaries from the workpiece perimeter to the workpiece center. In oneembodiment, the plate 208′ is fabricated from a non-conducting materialthat can block the electric field as it passes from the plane of theanode 212 to the plane of surface of the workpiece 30. The plate 208′has a substantially circular shape. The plate 208′ can include fasteningholes 314 for connecting the plate 208′ to the housing 200 or 200′, orto a support feature (not shown) that suspends the plate 208′ in thehousing 200 or 200′.

In one embodiment, the plate 208 (shown in FIGS. 10 and 11) or 208′(shown in FIG. 20) shapes the electric field incident on a surface ofthe workpiece 30. A body 316 of the plate 208 or 208′ can define aplurality of holes 320. The holes 320 can have a distribution of holesizes, e.g., the diameter of the holes can vary on a surface of theplate. By varying the distribution of hole sizes, the average open areaof a surface of the plate 208 or 208′ can be varied, and a property ofthe electric field passing through the plate 208 or 208′ to the surfaceof the workpiece 30 can be varied. The property of the electric fieldthat is varied can be amplitude or potential. In various embodiments,the electric field proximate to the surface of the workpiece can beuniform.

In one embodiment, the distribution of hole sizes comprises a continuousgradient of hole size. In one detailed embodiment, the holes vary in asubstantially radial pattern. For example, as illustrated in FIG. 20,larger holes can be formed near the center of the plate 208′ whilesmaller holes are formed closer to the outer perimeter of the plate208′. In various embodiments, the plate can have between about 500 andabout 10,000 holes, although more or fewer holes can be used dependingon the application and/or the workpiece size. In one embodiment, theplate can have between about 1,000 and about 5,000 holes. In onedetailed embodiment, the plate 208 or 208′ can have about 3000 holes andbe suitable for a 200 mm workpiece. In various embodiments, the diameterof the holes is between about 0.1 mm and about 20 mm, although largerand smaller diameter holes can be used depending on the application. Inone embodiment, the largest diameter holes can be about 5 mm indiameter. The smallest diameter holes can have a diameter of about 1 mm.

FIGS. 21A and 21B show an illustrative embodiment of a loading station14′, which can be used to load one or more workpieces 30 on anembodiment of the workpiece holder 18. FIGS. 21A and 21B include aholder 324 for the workpiece holder 18, a base member 328 for moving aworkpiece 30, and an arm 332 connecting the holder 324 and the basemember 328. FIG. 21B shows workpieces 30 loaded onto the base member328. The arm 332 and the holder 324 can include a hinged connection 336so that the arm 332 can move the base member 328 between a substantiallyhorizontal position and a substantially vertical position, or to anintermediate position. The base member 328 and the arm 332 can becomponents of the same piece.

The holder 324 can retain the workpiece holder 18 while workpieces 30are being loaded onto or removed from the workpiece holder 18. In someembodiments, the holder 324 can retain the workpiece holder 18 whileworkpieces 30 are being loaded onto or removed from the base member 328.The holder 324 can be a suitable metal, plastic, or polymer material. Asecond end effector (not shown) can be used to load a workpiece 30 ontothe base 328. The loading station 14′ can be coupled to a hydraulicmechanism and/or a computer to control the position of the arm 332.

In various embodiments, the base member 328 can include an end effector340 positioned in the central portion of the base member 328 and a chuck344 positioned around the outer perimeter of the base member 328. Theend effector 340 can be a Bernoulli end effector, an electrostaticchuck, or a vacuum end effector. The end effector 340 can retain aworkpiece 30 without contacting it. In some embodiments, the chuck 344is a vacuum chuck or a suction chuck. The chuck 344 can retain the ring42 on the base member 328. In one embodiment, the end effector 340 canretain the workpiece 30 against the ring 42 while the workpiece 30 isloaded onto or removed from the workpiece holder 18. In one embodiment,the end effector 340 can retain the workpiece 30 against the ring 42without contacting the workpiece 30.

In one embodiment, to load a workpiece 30 onto the workpiece holder 18,the ring 42 is engaged by the chuck 344. The workpiece 30 can be placedon the ring 42. The end effector 340 can be activated to hold theworkpiece 30 against the ring 42. The arm 332 can be moved to asubstantially vertical position. The workpiece holder 18 can engage thering 42. The end effector 340 can be disengaged from the workpiece 30,and the chuck 344 can be disengaged from the ring 42. The arm 332 can bemoved from the plane of the workpiece holder 18 so that there isclearance. The workpiece holder 18 can be removed from the holder 324and directed to a module for processing. The steps need not be completedin this order to load the workpiece 30.

In one embodiment, to remove a workpiece 30 from the workpiece holder18, the arm 332 can be moved to a substantially vertical position. Theend effector 340 can engage the workpiece 30, and the chuck 344 canengage the ring 42. The ring 42 is disengaged from the workpiece holder18. The arm 332 can be moved to a substantially horizontal position. Thesteps need not be completed in this order to remove the workpiece 30.

The loading station 14′ can load a single workpiece 30 to a workpieceholder 18, or can load a plurality of workpieces 30 to a workpieceholder 18. In one embodiment, two workpieces are loaded onto theworkpiece holder 18 substantially concurrently. In one embodiment, twoworkpieces are removed from the workpiece holder 18 substantiallyconcurrently. In some embodiments, a first workpiece is loaded onto orremoved from the workpiece holder 18 before a second workpiece is loadedor removed.

While the invention has been particularly shown and described withreference to specific illustrative embodiments, it should be understoodthat various changes in form and detail may be made without departingfrom the spirit and scope of the invention as defined by the appendedclaims. For example, although specific actions, movements, and processesmay be described with reference to specific embodiments, these actions,movements, and processes may be performed by any embodiment employinglike or similar features. Likewise, although the invention, in someembodiments, is described as a system employing individual features,some of the features can be utilized independent of the system.

1. An apparatus for fluid sealing a workpiece, comprising: a memberdefining at least one retaining feature; and a ring comprising at leastone engagement feature engageable with the at least one retainingfeature of the member; wherein the member is flexed to provide a forceto the at least one engagement feature to cause the ring to form abarrier to fluid entry with the workpiece.
 2. The apparatus of claim 1wherein the force causes the member to pull the at least one engagementfeature of the ring to cause the ring-to push against the workpiece toform the barrier to fluid entry.
 3. The apparatus of claim 1 wherein themember comprises at least one flex feature adapted to provide the forcesubstantially normal to the plane of the member to form the barrier tofluid entry.
 4. The apparatus of claim 1 wherein the member defines aplurality of flex features positioned about a perimeter of the member toprovide the force at least substantially uniformly from the perimeter ofthe member.
 5. The apparatus of claim 1 further comprising a backingmember adapted to apply a force to flex the member.
 6. The apparatus ofclaim 5 wherein the backing member comprises push pins to contact themember.
 7. The apparatus of claim 5 further comprising an inflatablebladder adjacent the backing member for moving the backing member toapply the force to flex the member.
 8. The apparatus of claim 1 furthercomprising a workpiece holder to which the member and the ring areremovably attached.
 9. The apparatus of claim 8 wherein the membercomprises at least one tab section for engaging at least one toothfeature of the workpiece holder.
 10. The apparatus of claim 1 whereinthe ring comprises a first elastomer region for forming the barrier tofluid entry with a surface of the workpiece.
 11. The apparatus of claim8 wherein the ring comprises a second elastomer region for forming asecond barrier to fluid entry with a surface of the workpiece holder.12. The apparatus of claim 1 wherein the ring comprises at least onecontact adapted to form an electrical connection with the workpiece. 13.The apparatus of claim 1 wherein the workpiece has a substantiallynon-circular shape.
 14. The apparatus of claim 8 wherein the workpieceholder defines a hole that passes from a first surface to a secondsurface, the diameter being smaller than the diameter of the ring, thehole for processing a plurality of surfaces of the workpiece.
 15. Amethod of fluid sealing a workpiece, comprising: placing a workpiece ona ring; engaging at least one engagement feature of the ring with atleast one retaining feature defined by a member; and flexing the memberto provide a force to the at least one engagement feature to cause thering to form a barrier to fluid entry with the workpiece.
 16. The methodof claim 15 wherein the force causes the member to pull the at least oneengagement feature of the ring to cause the ring to push against theworkpiece to form the barrier to fluid entry.
 17. The method of claim 15further comprising providing the force at least substantially uniformlyfrom a perimeter of the member via a plurality of flex featurespositioned about the perimeter.
 18. The method of claim 15 furthercomprising rotating the ring to lock the at least one engagement featureof the ring into the at least one retaining feature of the member. 19.The method of claim 15 further comprising applying the forcesubstantially normal to the plane of the member using at least one flexfeature of the member.
 20. The method of claim 15 further comprisingmoving a backing member to flex the member.
 21. The method of claim 20further comprising deflating a bladder to move the backing member awayfrom the member.
 22. The method of claim 15 further comprising testingthe integrity of the barrier to fluid entry.
 23. The method of claim 15wherein the member includes an over-extended state in which the at leastone retaining feature captures the at least one engagement feature ofthe ring prior to flexing the member.
 24. The method of claim 15 furthercomprising depositing a metal or a plastic on a surface of theworkpiece.
 25. The method of claim 15 further comprising dissoluting ametal or a plastic on a surface of the workpiece.
 26. The method ofclaim 15 further comprising processing a plurality of surfaces of theworkpiece via a hole defined by the workpiece holder, the hole passingfrom a first surface of a workpiece holder to a second surface of theworkpiece holder, the diameter of the hole being smaller than thediameter of the ring.
 27. An apparatus for applying force to an object,comprising: a substantially planar, ring-shaped member defining aplurality of flex features positioned about a perimeter of the member,the plurality of flex features providing a force at least substantiallyuniformly around the perimeter of the object when the member is flexed.28. The apparatus of claim 27 wherein the force is providedsubstantially normal to the plane of the member.
 29. The apparatus ofclaim 27 wherein the member defines at least one retaining featureengageable with at least one engagement feature of a ring.
 30. Theapparatus of claim 29 wherein the ring retains the object while theforce is applied.
 31. The apparatus of claim 27 wherein the object has asubstantially non-circular shape.
 32. The apparatus of claim 27 furthercomprising a backing member adapted to apply a force to flex the member.33. The apparatus of claim 32 wherein the backing member comprises pushpins to contact the member.
 34. The apparatus of claim 31 furthercomprising an inflatable bladder adjacent the backing member for movingthe backing member to apply the force to flex the member.
 35. Theapparatus of claim 29 further comprising a workpiece holder to which themember and the ring are removably attached.
 36. The apparatus of claim35 wherein the member comprises at least one tab section for engaging atleast one tooth feature of the workpiece holder.
 37. The apparatus ofclaim 27 wherein the force retains the object against a portion of asurface of a workpiece holder.
 38. The apparatus of claim 27 wherein theplurality of flex features are positioned about an inner perimeter ofthe member.
 39. The apparatus of claim 27 wherein the plurality of flexfeatures are positioned about an outer perimeter of the member.
 40. Theapparatus of claim 27 wherein the plurality of flex features arepositioned about both the inner and outer perimeters of the member. 41.The apparatus of claim 27 wherein the member comprises a spring-likematerial.
 42. The apparatus of claim 27 wherein the member comprisesstainless steel or titanium.
 43. The apparatus of claim 35 wherein theworkpiece holder defines a hole that passes from a first surface to asecond surface of the workpiece holder, the diameter being smaller thanthe diameter of the ring, the hole for processing a plurality ofsurfaces of the object.
 44. A method for applying a uniform force to anobject, comprising: providing a member having a substantially planar,ring shape; providing a plurality of flex features positioned about aperimeter of the member; and flexing the member to provide a force fromthe plurality of flex features at least substantially uniformly aroundthe perimeter of an object.
 45. The method of claim 44 furthercomprising providing the force substantially normal to the plane of themember.
 46. The method of claim 44 further comprising retaining theobject with a ring while the force is applied.
 47. The method of claim48 further comprising rotating the ring to lock at least one engagementfeature of the ring into at least one retaining feature defined by themember.
 48. The method of claim 44 wherein the object has asubstantially non-circular shape.
 49. The method of claim 46 furthercomprising retaining the object against a portion of a surface of aworkpiece holder.
 50. The method of claim 44 wherein the plurality offlex features are positioned about an inner perimeter of the member. 51.The method of claim 44 wherein the plurality of flex features arepositioned about an outer perimeter of the member.
 52. The method ofclaim 44 wherein the plurality of flex features are positioned aboutboth the inner and outer perimeters of the member.
 53. The method ofclaim 49 further comprising processing a plurality of surfaces of theobject via a hole defined by the workpiece holder, the hole passing froma first surface to a second surface of the workpiece holder, thediameter of the hole being smaller than the diameter of the ring.
 54. Anapparatus for fluid sealing a workpiece, comprising: a first meansdefining at least one retaining feature; a ring comprising at least oneengagement means engageable with the at least one retaining feature; anda second means for flexing the first means to provide a force to the atleast one engagement means to cause the ring to form a barrier to fluidentry with the workpiece.
 55. An apparatus for applying force to anobject, comprising: a substantially planar ring-shaped member defining aplurality of flex features positioned about a perimeter of the member;and a means for flexing the member to provide a force from the pluralityof flex features at least substantially uniformly around the perimeterof an object.